another supporter of MEC booties, have had the same pair for ages. As stated, if you dont walk around in them too much on cement, they will last for as long as Ive had mine, probably well over 10 years.
Very good rain protection, as blue says, they dont cover the soles which is good for some airing out if it is warm and I too have never had serious problems with being sweaty in them (a bit, but that is normal if it is hot)
ditto on having to use rain pants or rain will just go in top.
ditto also having used them much more for cool weather wind protection. With thick wool socks, I use them regularly down to close to freezing as I tend to ride into December here and they make rides in the 2, 3 C and up temp comfortable for my feet (socks important tho of course)
I would not travel without them.